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Publication Number: FHWA-SA-98-020
Date: March 1998
When the Asphalt Technical Working Group (TWG) was created in 1993, its mission was to evaluate the Superpave system and to develop plans for getting the Superpave specifications and devices into the hands of users. As part of its work, the TWG set ambitious target dates of 1997 for implementation of the Superpave binder specification and 2000 for implementation of the Superpave volumetric mix design procedures. More than half of the States have hit the first target, and nearly three-quarters plan to meet the second target date. But the TWG's work is far from over. Now that the Superpave system is becoming standard practice for asphalt paving projects, State highway agencies and contractors are seeking advice on construction, training, and other issues related to the Superpave system. Last fall, the TWG crafted and adopted a new strategic plan that will help it meet the States' new needs.
A new contest offers students at campuses around the world an opportunity to influence the pavement design and maintenance strategies of the future. Designed primarily for engineering students and sponsored by the American Society of Civil Engineers (ASCE) and the Federal Highway Administration (FHWA), the contest involves using data from the long-term pavement performance (LTPP) studies. Students, who are encouraged to team up with a highway agency or a consulting firm, determine the research objective, conduct the research, and analyze the data. The findings are then submitted in the form of a paper for evaluation.
In a 1995 survey of motorists nationwide, pavement conditions topped the list of priority areas for improvement in the Nation's highway system. That was no surprise to the Georgia Department of Transportation (DOT), one of the members of the Lead States team for pavement preservation and a strong proponent of pavement preservation through a systematic approach to preventive maintenance. For more than 20 years, Georgia DOT has strived to satisfy its customers by making smoother pavements a goal of its pavement preservation strategy.
Mike Halladay, FHWA's SHRP implementation coordinator since 1996, was recently named chief of the Technology Management Division within the FHWA Office of Technology Applications. He replaces Ray Griffith, who is retiring after 32 years of service with FHWA and 7.5 years of service prior to that with the Kansas Highway Commission. The Technology Management Division provides operations and support services (including publishing Focus) for FHWA's technology transfer programs and administers the Local Technical Assistance Program.
In the past 2 years, State highway agencies have built more than 400 Superpave pavements. For most of these pavements, construction went smoothly, with no more problems than would be experienced with conventional asphalt pavements. However, highway agencies and contractors have learned through the school of hard knocks that Superpave mixes don't always behave like conventional asphalt mixes.
Soon after opening to traffic last year, the outside lanes of a newly overlaid section of Interstate 74 in Indiana showed signs of severe flushing. The overlay had been designed using the Superpave mix design system. A team of engineers went to work to figure out what went wrong-and why. They concluded that what happened on I-74 was likely caused by an unusual combination of factors.
The team of independent experts investigating the premature rutting at WesTrack has finished its final report, and the report is scheduled to be available next month. The investigative team was assembled last fall after several test sections at the Federal Highway Administration's (FHWA) hot-mix asphalt test track in Nevada developed rutting after carrying traffic for just a few days.
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